Former boxing champion Chris van Heerden doesn’t like UFC Lightweight Champion Conor McGregor’s chances against Floyd “Money” Mayweather in a boxing match.

Heerden has experience sparring with the UFC champion in boxing. After boxing with McGregor, he doesn’t think McGregor will do well against one of the greatest boxers of all time.

“I’m no Mayweather, and I was fat and out of shape, and I landed on McGregor,” Heerden told TMZ Sports. “I landed at will. It is crazy that people can actually compare a fighter that is 0-0 in boxing to a legend that is 49-0, and if you look at his resume he has beaten the best of the best in the world.”

Heerden also went on to say that McGregor does not have the power to knock out Mayweather, especially since they will be wearing 10 oz gloves.

“He’s been hit by guys that can punch, and he didn’t go down,” Heerden said about Mayweather.

Mayweather vs. McGregor will take place Aug. 26 at the T-Mobile Arena in Las Vegas.